Heat source control device, heat source system, and heat source control method

ABSTRACT

In a heat source control device, a heat source system, and a heat source control method, heat source groups, a plurality of group control units, and a number-of-units control unit are included. The group control units include a first operating-range output unit and a second operating-range output unit. When a requested load exceeds a first proper operating range, the number-of-units control unit increases the number of activated heat source groups and controls the group control units so that the number of activated heat source units is a predetermined number.

TECHNICAL FIELD

The present invention relates to a heat source control device, a heatsource system, and a heat source control method.

Priority is claimed on Japanese Patent Application No. 2013-228348,filed Nov. 1, 2013, the content of which is incorporated herein byreference.

BACKGROUND ART

In large buildings, chilled and hot water systems in which a pluralityof heat sinks and heat sources are provided in parallel andsecondary-side heat load sources such as air conditioners are connectedto the heat sinks and heat sources are used. Each of the heat sinks andheat sources includes a chilled and hot water pump circulating chilledand hot water generated by each of the heat sinks and heat sources.

In such chilled and hot water systems, necessary flow rates of chilledand hot water are changed to handle heat loads according tosecondary-side loads. Accordingly, in such chilled and hot watersystems, flow rates of chilled and hot water to be supplied tosecondary-side heat load sources have to be controlled.

As such chilled and hot water control methods, there are methods ofcontrolling bypass flow rates of secondary-side heat load sources andcontrolling the numbers of heat sinks and heat sources. In such a methodof controlling the numbers of heat sinks and heat sources, the number ofoperating heat sinks and heat sources is selected in accordance withschemes considering flow rates, heat amounts, and both of flow rates andheat amounts.

In this case, chilled and hot water pumps of the used heat sinks andheat sources circulate chilled and hot water by changing flow ratesaccording to loads.

As technologies related to such a background, various technologies areknown (for example, see Patent Literature 1).

For example, Patent Literature 1 discloses a heat sink and heat sourceoutput distribution control method of a chilled and hot water systemthat includes a plurality of heat sinks and heat sources disposed inparallel, chilled and hot water pumps included in the heat sinks andheat sources, and a secondary-side heat load source connected to theplurality of heat sinks and heat sources. More specifically, in the heatsink and heat source output distribution control method, the number ofheat sinks and heat sources to be used is selected according to heatloads of secondary-side heat sources. In the heat sink and heat sourceoutput distribution control method, when a plurality of heat sinks andheat sources are used, the heat sinks and heat sources to be used aredivided into two groups which each have one heat sink and one heatsource or a plurality of heat sinks and heat sources, and a ratio of aflow rate of chilled and hot water of the heat sinks and heat sources ofboth groups to a flow rate of chilled and hot water supplied to thesecondary-side heat load source is changed so that a sum system COP ofthe two groups of the heat sinks and heat sources is the maximum. Theflow rate is changed in a direction in which a ratio of one groupincreases in accordance with a predetermined period and the system COPis calculated. When the system COP increases more than the system COPbefore the change, the flow rate is changed in the same direction. Whenthe system COP decreases, the flow rate is changed in the oppositedirection. In this way, according to the heat sink and heat sourceoutput distribution control method, the heat sinks and heat sources workwith the maximum efficiency from the viewpoint of the entire system, andthus power consumption can be reduced.

CITATION LIST Patent Literature [Patent Literature 1]

Japanese Patent No. 4435651

SUMMARY OF INVENTION Technical Problem

In the invention described in Patent Literature 1, when the numbers ofheat sinks and heat sources increase, a control period may increase, andthus there is a possibility that a load state to be handled is changed.Therefore, in the invention described in Patent Literature 1, searchresults may not always be optimum.

In the invention described in Patent Literature 1, when group control isperformed and the same function of a number-of-units control functionmounted on a high-order control device is mounted, a load range that canbe handled with one group becomes broader than a load range that can behandled with one unit. Therefore, in the invention described in PatentLiterature 1, for example, when ten units are operating in an operatinggroup and another group is newly activated in this state, sudden changesin control may be performed in such a manner that the number ofoperating units of the operating group is changed from 10 to 5 and thenumber of operating units of the newly activated group is changed from 0to 5. Therefore, control may not be performed to prevent the number ofoperating units connected to the group from changing suddenly.

Solution to Problem

According to a first aspect of the present invention, there is provideda heat source control device including: a plurality of group controlunits configured to perform start/stop and load allocation of aplurality of heat source units corresponding to heat source groups ofthe plurality of heat source units; and a number-of-units control unitconfigured to perform start/stop and load allocation of the heat sourcegroups. The group control unit includes a first operating-range outputunit configured to output a load range in which one of characteristicvalues of the heat source units corresponding to the number of operatingheat source units is within a predetermined range as a first properoperating range to the number-of-units control unit based on thecharacteristic values of the heat source units, and a secondoperating-range output unit configured to output a load range in whichanother of the characteristic values is in the predetermined range as asecond proper operating range to the number-of-units control unit. Thenumber-of-units control unit increases the number of activated heatsource groups when a requested load exceeds the first proper operatingrange.

According to a second aspect of the present invention, in the heatsource control device according to the first aspect, the firstoperating-range output unit may use COP information indicating arelation between a coefficient of performance and a load ratio as thecharacteristic value and output a load range in which one of thecharacteristic values corresponding to the number of operating heatsource units is equal to or greater than a predetermined value as thefirst proper operating range to the number-of-units control unit. Thesecond operating-range output unit may output a load range in whichanother of the characteristic values is equal to or greater than thepredetermined value as the second proper operating range to thenumber-of-units control unit.

According to a third aspect of the present invention, in the heat sourcecontrol device according to the first aspect, the first operating-rangeoutput unit may use inverter input information as the characteristicvalue and output a load range in which one of the characteristic valuescorresponding to the number of operating heat source units is equal toor less than a predetermined value as the first proper operating rangeto the number-of-units control unit. The second operating-range outputunit may output a load range in which another of the characteristicvalues is equal to or less than the predetermined value as the secondproper operating range to the number-of-units control unit.

According to a fourth aspect of the present invention, in the heatsource control device according to any one of the first to thirdaspects, the group control unit may set, as transmission data from thegroup control unit, an optimum load range corresponding to the number ofoperating heat source units among the connected heat source units and anoperatable load range corresponding to 1+the number of operating heatsource units.

According to a fifth aspect of the present invention, in the heat sourcecontrol device according to any one of the first to fourth aspects, whenload distribution to the heat source groups from the number-of-unitscontrol unit is greater than the operatable load range for the number ofoperating heat source units, the number of operating heat source unitsin the heat source group may be increased and the optimum load range andthe operatable load range may be updated.

According to a sixth aspect of the present invention, in the heat sourcecontrol device according to any one of the first to fifth aspects, whenload distribution to the heat source groups from the number-of-unitscontrol unit is less than the operatable load range for the number ofoperating heat source units, the number of operating heat source unitsin the heat source group may be decreased and the optimum load range andthe operatable load range may be updated.

According to a seventh aspect of the present invention, there isprovided a heat source system including: the heat source control deviceaccording to any one of the first to sixth aspects; and heat sourcegroups of the plurality of heat source units.

According to an eighth aspect of the present invention, there isprovided a heat source control method including: a plurality of groupcontrol steps of performing start/stop and load allocation of aplurality of heat source units corresponding to heat source groups ofthe plurality of heat source units; and a number-of-units control stepof performing start/stop and load allocation of the heat source groups.The group control step includes a first operating-range output step ofoutputting a load range in which one of characteristic values of theheat source units corresponding to the number of operating heat sourceunits is within a predetermined range as a first proper operating rangein the number-of-units control step based on the characteristic valuesof the heat source units, and a second operating-range output step ofoutputting a load range in which another of the characteristic values isin the predetermined range as a second proper operating range in thenumber-of-units control step. In the number-of-units control step, thenumber of activated heat source groups is increased when a requestedload exceeds the first proper operating range.

In the overview of the first to eighth aspects of the present invention,not all of the characteristics necessary in the present invention arelisted. Sub-combinations of such characteristic groups can also beaspects of the present invention.

Advantageous Effects of Invention

According to the heat source control device, the heat source system, andthe heat source control method described above, it is possible tocontrol the number of operating heat source units included in theplurality of heat source groups without sudden changes.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an example of the system configurationof a heat source system 100 according to a first embodiment.

FIG. 2 is a block diagram illustrating the configurations of groupcontrol devices 11 and 21.

FIG. 3 is a diagram illustrating COP characteristics applied to the heatsource system 100.

FIG. 4 is a diagram illustrating power consumption amountcharacteristics applied to the heat source system 100.

FIG. 5 is a flowchart for describing a basic control operation of theheat source system 100.

FIG. 6 is a flowchart for describing a specific control operation of theheat source system 100.

FIG. 7 is a flowchart for describing the specific control operation ofthe heat source system 100.

FIG. 8 is a flowchart for describing a basic control operation of a heatsource system 100 according to a second embodiment.

FIG. 9 is a flowchart for describing a basic control operation of a heatsource system 100 according to a third embodiment.

DESCRIPTION OF EMBODIMENTS

Hereinafter, the present invention will be described according toembodiments of the invention. However, the following embodiments do notlimit the invention within the scope of the claims, and not all of thecombinations of the characteristics described in the embodiments arerequisites for the solution of the invention.

FIG. 1 is a diagram illustrating an example of the system configurationof a heat source system 100 according to a first embodiment. Here, theheat source system 100 is a system that controls a plurality of heatsources.

The heat source system 100 includes a first heat source group 10, afirst group control device 11, a second heat source group 20, a secondgroup control device 21, and a number-of-units control device 30.

The first heat source group 10 includes a plurality of heat source units12. Here, the heat source unit 12 is a unit that includes a heat sourcedevice and a unit-integrated control device 13. An input side of eachheat source unit 12 is connected to communicate with a water inlet 41and an output side thereof is connected to communicate with a wateroutlet 42. The output side of each heat source unit 12 is connected tothe first group control device 11 and the number-of-units control device30.

When the first group control device 11 controls the heat source units12, the first group control device 11 receives necessary data from theunit-integrated control device 13 and transmits control data to theunit-integrated control device 13. Then, the first group control device11 performs start/stop and load allocation of each heat source unit 12.

The second heat source group 20 is connected to the first heat sourcegroup 10 in parallel and includes a plurality of heat source units 22.Here, the heat source unit 22 is a unit that includes a heat sourcedevice and a unit-integrated control device 23. An input side of eachheat source unit 22 is connected to communicate with the water inlet 41and an output side thereof is connected to communicate with the wateroutlet 42. The output side of each heat source unit 22 is connected tothe second group control device 21 and the number-of-units controldevice 30. When the second group control device 21 controls the heatsource units 22, the second group control device 21 receives necessarydata from the unit-integrated control device 23 and transmits controldata to the unit-integrated control device 23. Here, the data receivedfrom the unit-integrated control device 23 also includes COP informationindicating a relation between a coefficient of performance and a loadratio of the heat source units 12 and 22.

The first group control device 11 performs start/stop and loadallocation of each heat source unit 22.

The number-of-units control device 30 performs start/stop and loadallocation of the first heat source group 10 and the second heat sourcegroup 20. From the viewpoint of the number-of-units control device 30,the first heat source group 10 and the second heat source group 20 areeach treated like a large-capacity chiller.

FIG. 2 is a block diagram illustrating the configurations of the groupcontrol devices 11 and 21. As illustrated in FIG. 2, the group controldevices 11 and 21 respectively include first operating-range outputunits 14 and 24 that output a load range in which a coefficient ofperformance corresponding to the number of operating heat source units12 and 22 is equal to or greater than a predetermined value as a firstproper operating range to the number-of-units control device 30 based onthe COP information which is a characteristic value indicating therelation between the coefficient of performance and the load ratio ofthe heat source units 12 and 22.

The group control devices 11 and 21 respectively include secondoperating-range output units 15 and 25 that output a load range in whicha coefficient of performance corresponding to the predetermined numberof units greater than the operating heat source units 12 and 22 is equalto or greater than a predetermined value as a second proper operatingrange to the number-of-units control device 30 based on the COPinformation.

The number-of-units control device 30 increases the number of activatedunits of each of the heat source groups 10 and 20 when a requested loadexceeds the first proper operating range.

The heat source system 100 sets an optimum load range corresponding tothe number of operating units among the heat source units 12 and 22respectively connected to the group control devices 11 and 21 and anoperatable load range corresponding to 1+the number of operating unitsas data to be transmitted from the group control devices 11 and 21 tothe number-of-units control device 30.

Specifically, for example, when ten heat source units 12 are connectedto the first group control device 11 and one heat source unit isoperating, an optimum load range for one unit and an operatable loadrange for two units are set as an optimum load range and an operatableload range of the whole group.

When all of the units stop among the heat source units 12 and 22respectively connected to the group control devices 11 and 21, the heatsource system 100 sets an optimum load range and an operatable loadrange for one unit as data to be transmitted from the group controldevices 11 and 21 to the number-of-units control device 30.

When the operating heat source units are in the heat source groups 10and 20, the number-of-units control device 30 sets optimum load rangesand operatable load ranges of both of the heat source groups 10 and 20using the following Expressions (1) to (12).

In Expressions (1) to (6), Loh_gi and Lol_gi are a Hi-side and a Lo-sideof the optimum load range of each of the heat source groups 10 and 20,Lh_gi and Ll_gi are a Hi-side and a Lo-side of the operatable loadrange, and Loph_gi and Lopl_gi are a Hi-side and a Lo-side of theoperatable load range of the operating unit (where i=1 to 20). Further,Loh_gkui and Lol_gkui are a Hi-side and a Lo-side of the optimum loadrange of each of the heat source units 12 and 22, Lh_gkui and Ll_gkuiare a Hi-side and a Lo-side of the operatable load range (where k=1 to 6and i=1 to 20), and m is the number of operating units.

$\begin{matrix}{L_{{oh}\_ {gi}} = {\sum\limits_{k = 1}^{m}\; L_{{oh}\_ {giu}k}}} & \lbrack {{Expression}\mspace{14mu} 1} \rbrack \\{L_{{ol}\_ {gi}} = {\sum\limits_{k = 1}^{m}\; L_{{ol}\_ {giu}k}}} & \lbrack {{Expression}\mspace{14mu} 2} \rbrack \\{L_{h\_ {gi}} = {\sum\limits_{k = 1}^{m + 1}\; L_{h\_ {giu}k}}} & \lbrack {{Expression}\mspace{14mu} 3} \rbrack \\{L_{l\_ {gi}} = {\sum\limits_{k = 1}^{m}\; L_{l\_ {giu}k}}} & \lbrack {{Expression}\mspace{14mu} 4} \rbrack \\{L_{{oph}\_ {gi}} = {\sum\limits_{k = 1}^{m}\; L_{h\_ {giu}k}}} & \lbrack {{Expression}\mspace{14mu} 5} \rbrack \\{L_{{opl}\_ {gi}} = {\sum\limits_{k = 1}^{m}\; L_{l\_ {giu}k}}} & \lbrack {{Expression}\mspace{14mu} 6} \rbrack\end{matrix}$

In Expressions (7) to (12), Loh_gi and Lol_gi are a Hi-side and aLo-side of the optimum load range of each of the heat source groups 10and 20, and Lh_gi and Ll_gi are a Hi-side and a Lo-side of theoperatable load range (where i=1 to 20). Further, Loh_gkui and Lol_gkuiare a Hi-side and a Lo-side of the optimum load range of each of theheat source units 12 and 22, Lh_gkui and Ll_gkui are a Hi-side and aLo-side of the operatable load range (where k=1 to 6 and i=1 to 20), andthe number of operating units is 0.

$\begin{matrix}{L_{{oh}\_ {gi}} = {\sum\limits_{k = 1}^{m}\; L_{{oh}\_ {giu}k}}} & \lbrack {{Expression}\mspace{14mu} 7} \rbrack \\{L_{{ol}\_ {gi}} = {\sum\limits_{k = 1}^{m}\; L_{{ol}\_ {giu}k}}} & \lbrack {{Expression}\mspace{14mu} 8} \rbrack \\{L_{h\_ {gi}} = {\sum\limits_{k = 1}^{m + 1}\; L_{h\_ {giu}k}}} & \lbrack {{Expression}\mspace{14mu} 9} \rbrack \\{L_{l\_ {gi}} = {\sum\limits_{k = 1}^{m}\; L_{l\_ {giu}k}}} & \lbrack {{Expression}\mspace{14mu} 10} \rbrack \\{L_{{oph}\_ {gi}} = {\sum\limits_{k = 1}^{m}\; L_{h\_ {giu}k}}} & \lbrack {{Expression}\mspace{14mu} 11} \rbrack \\{L_{{opl}\_ {gi}} = {\sum\limits_{k = 1}^{m}\; L_{l\_ {giu}k}}} & \lbrack {{Expression}\mspace{14mu} 12} \rbrack\end{matrix}$

FIG. 3 is a diagram illustrating COP characteristics applied to the heatsource system 100. Information regarding the COP characteristicsindicates a relation between the coefficient of performance and a loadratio of each of the heat source units 12 and 22 and includes datareceived from the unit-integrated control device 23. In FIG. 3, thehorizontal axis represents a chiller output capacity and the verticalaxis represents a COP value. As illustrated in FIG. 3, in the COPcharacteristics, the COP has a parabolic shape according to an increasein the chiller output capacity when outside air temperature is, forexample, 15° C., 25° C., and 32° C. At this time, the proper operatingrange is a load range equal to or greater than a predetermined value.

FIG. 4 is a diagram illustrating power consumption amountcharacteristics applied to the heat source system 100. In FIG. 4, thehorizontal axis represents a chiller output capacity and the verticalaxis represents an inverter input. As illustrated in FIG. 4, in powerconsumption amount characteristics, power consumption increases directlyproportionally with an increase in the chiller output capacity when anoutside air temperature is, for example, 15° C., 25° C., and 32° C. Atthis time, the proper operating range is a load range equal to or lessthan a predetermined value.

FIG. 5 is a flowchart for describing a basic control operation of theheat source system 100. As illustrated in FIG. 5, when the controlstarts, the number-of-units control device 30 first determines whetherthe operating heat source unit is in either of the heat source groups 10and 20 (S101).

When the operating unit is in either of the heat source groups 10 and20, the number-of-units control device 30 decides the optimum load rangeand the operatable load range of both of the heat source groups 10 and20 according to the above-described Expressions (1) to (6) (S102).

When the operating unit is not present in either of the heat sourcegroups 10 and 20, the number-of-units control device 30 decides theoptimum load range and the operatable load range of both of the heatsource groups 10 and 20 according to the above-described Expressions (7)to (12) (S103).

FIGS. 6 and 7 are flowchart for describing a specific control operationof the heat source system 100. FIG. 6 illustrates a case in which thefirst heat source group 10 works first. As illustrated in FIG. 6, whenthe control starts, the number-of-units control device 30 first startsoperating and issues a group operating instruction (S111). The groupoperating instruction is transmitted to the first group control device11, and thus the first group control device 11 starts operating (S112).

The first group control device 11 transmits the optimum load range andthe operatable load range calculated from Expressions (1) to (6) to thenumber-of-units control device 30 (S113). The optimum load range and theoperatable load range are periodically transmitted to thenumber-of-units control device 30.

At this time, the second group control device 21 transmits the optimumload range and the operatable load range calculated according toExpressions (7) to (12) to the number-of-units control device 30 (S114).The optimum load range and the operatable load range are periodicallytransmitted to the number-of-units control device 30.

The number-of-units control device 30 determines whether a request loadis greater than the optimum load range during the operating (S115). Thesecond group control device 21 starts operating when the number-of-unitscontrol device 30 determines that the request load is greater than theoptimum load range during the operating (S116).

Thereafter, the first group control device 11 periodically transmits theoptimum load range and the operatable load range calculated according toExpressions (1) to (6) to the number-of-units control device 30 (S117).

The second group control device 21 periodically transmits the optimumload range and the operatable load range calculated according toExpressions (1) to (6) (S118).

Next, the number-of-units control device 30 transmits load allocation tothe first group control device 11 and the second group control device21. The first group control device 11 determines whether the allocatedload is greater than a load range that can be handled with the number ofoperating units (S119). When the first group control device 11determines that the load allocated by the number-of-units control device30 is greater than the load range that can be handled with the number ofoperating units, the first group control device 11 increases the numberof operating units in the heat source group (S120). Conversely, when thefirst group control device 11 determines that the load allocated by thenumber-of-units control device 30 is not greater than the load rangethat can be handled with the number of operating units, the first groupcontrol device 11 does not change the number of operating units.

The second group control device 21 determines whether the allocated loadis greater than the load range that can be handled with the number ofoperating units (S121). When the second group control device 21determines that the load allocated by the number-of-units control device30 is greater than the load range that can be handled with the number ofoperating units, the second group control device 21 increases the numberof operating units in the heat source group (S122). Conversely, when theload allocated by the number-of-units control device 30 is not greaterthan the load range that can be handled with the number of operatingunits, the second group control device 21 does not change the number ofoperating units.

Subsequently, the first group control device 11 determines whether theallocated load is less than the load range that can be handled with thenumber of operating units (S123). When the first group control device 11determines that the load allocated by the number-of-units control device30 is less than the load range that can be handled with the number ofoperating units, the first group control device 11 decreases the numberof operating units in the heat source group (S124). Conversely, when theload allocated by the number-of-units control device 30 is not less thanthe load range that can be handled with the number of operating units,the first group control device 11 does not change the number ofoperating units.

The second group control device 21 determines whether the allocated loadis less than the load range that can be handled with the number ofoperating units (S125). When the second group control device 21determines that the load allocated by the number-of-units control device30 is less than the load range that can be handled with the number ofoperating units, the second group control device 21 decreases the numberof operating units in the heat source group (S126). When the secondgroup control device 21 determines that the load allocated by thenumber-of-units control device 30 is not less than the load range thatcan be handled with the number of operating units, the second groupcontrol device 21 does not change the number of operating units.

The number-of-units control device 30 determines whether the requestedload is less than the optimum load range during the operating (S127).When the number-of-units control device 30 determines that the requestedload is less than the optimum load range during the operating, a stopinstruction is issued to the first group control device 11, and thus theoperating of the first group control device 11 ends (S128). At thistime, when the operating group is only one first heat source group 10,the stop instruction is not issued.

When the number-of-units control device 30 determines that the requestedload is not less than the optimum load range during the operating, thenumber-of-units control device 30 determines whether only the secondheat source group 20 is operating (S129). When the number-of-unitscontrol device 30 determines that only the second heat source group 20is operating, the process proceeds to (S145) illustrated in FIG. 7. Whenthe number-of-units control device 30 determines that only the secondheat source group 20 is not operating, the number-of-units controldevice 30 determines whether only the first heat source group 10 isoperating (S130). When the number-of-units control device 30 determinesthat only the first heat source group 10 is operating, the processproceeds to (S115). When the number-of-units control device 30determines that only the first heat source group 10 is not operating,the process proceeds to (S117) to repeat the routine.

FIG. 7 illustrates a case in which the second heat source group 20 worksfirst. As illustrated in FIG. 7, when the control starts, thenumber-of-units control device 30 first starts operating and issues agroup operating instruction (S141). The group operating instruction istransmitted to the second group control device 21, and thus the secondgroup control device 21 starts operating (S142).

The second group control device 21 transmits the optimum load range andthe operatable load range calculated from Expressions (1) to (6) to thenumber-of-units control device 30 (S143). The optimum load range and theoperatable load range are periodically transmitted to thenumber-of-units control device 30.

At this time, the first group control device 11 transmits the optimumload range and the operatable load range calculated according toExpressions (7) to (12) to the number-of-units control device 30 (S144).The optimum load range and the operatable load range are periodicallytransmitted to the number-of-units control device 30.

The number-of-units control device 30 determines whether a request loadis greater than the optimum load range during the operating (S145). Thefirst group control device 11 starts operating when the number-of-unitscontrol device 30 determines that the request load is greater than theoptimum load range during the operating (S146).

Thereafter, the first group control device 11 periodically transmits theoptimum load range and the operatable load range calculated according toExpressions (1) to (6) to the number-of-units control device 30 (S147).

The second group control device 21 periodically transmits the optimumload range and the operatable load range calculated according toExpressions (1) to (6) (S148).

Next, the number-of-units control device 30 transmits load allocation tothe first group control device 11 and the second group control device21. The first group control device 11 determines whether the allocatedload is greater than a load range that can be handled with the number ofoperating units (S149). When the first group control device 11determines that the load allocated by the number-of-units control device30 is greater than the load range that can be handled with the number ofoperating units, the first group control device 11 increases the numberof operating units in the heat source group (S150). Conversely, when thefirst group control device 11 determines that the load allocated by thenumber-of-units control device 30 is not greater than the load rangethat can be handled with the number of operating units, the first groupcontrol device 11 does not change the number of operating units.

The second group control device 21 determines whether the allocated loadis greater than the load range that can be handled with the number ofoperating units (S151). When the second group control device 21determines that the load allocated by the number-of-units control device30 is greater than the load range that can be handled with the number ofoperating units, the second group control device 21 increases the numberof operating units in the heat source group (S152). Conversely, when thesecond group control device 21 determines that the load allocated by thenumber-of-units control device 30 is not greater than the load rangethat can be handled with the number of operating units, the second groupcontrol device 21 does not change the number of operating units.

Subsequently, the first group control device 11 determines whether theallocated load is less than the load range that can be handled with thenumber of operating units (S153). When the first group control device 11determines that the load allocated by the number-of-units control device30 is less than the load range that can be handled with the number ofoperating units, the first group control device 11 decreases the numberof operating units in the heat source group (S154). Conversely, when thefirst group control device 11 determines that the load allocated by thenumber-of-units control device 30 is not less than the load range thatcan be handled with the number of operating units, the first groupcontrol device 11 does not change the number of operating units.

The second group control device 21 determines whether the allocated loadis less than the load range that can be handled with the number ofoperating units (S155). When the second group control device 21determines that the load allocated by the number-of-units control device30 is less than the load range that can be handled with the number ofoperating units, the second group control device 21 decreases the numberof operating units in the heat source group (S156). When the secondgroup control device 21 determines that the load allocated by thenumber-of-units control device 30 is not less than the load range thatcan be handled with the number of operating units, the second groupcontrol device 21 does not change the number of operating units.

The number-of-units control device 30 determines whether the requestedload is less than the optimum load range during the operating (S157).When the number-of-units control device 30 determines that the requestedload is less than the optimum load range during the operating, a stopinstruction is issued to the second group control device 21, and thusthe operating of the second group control device 21 ends (S158). At thistime, when the number-of-units control device 30 determines that theoperating group is only one second heat source group 20, the stopinstruction is not issued.

When the number-of-units control device 30 determines that the requestedload is not less than the optimum load range during the operating, thenumber-of-units control device 30 determines whether only the first heatsource group 10 is operating (S159). When the number-of-units controldevice 30 determines that only the first heat source group 10 isoperating, the process proceeds to (S115) illustrated in FIG. 6. Whenthe number-of-units control device 30 determines that only the firstheat source group 10 is not operating, the number-of-units controldevice 30 determines whether only the second heat source group 20 isoperating (S160). When the number-of-units control device 30 determinesthat only the second heat source group 20 is operating, the processproceeds to (S145). When the number-of-units control device 30determines that only the second heat source group 20 is not operating,the process proceeds to (S147) to repeat the routine.

As described above, the heat source system 100 according to theembodiment first performs the process of increasing the number of heatsource groups when the load departs from the optimum load range.Accordingly, in the heat source system 100, when only one heat sourceunit is operating between the heat source units 12 and 22 connected tothe heat source groups 10 and 20, the number of operating target heatsource groups can first be increased. Therefore, even when the load canbe equally distributed to the heat source groups 10 and 20, control canbe performed such that the number of operating heat source units 12 and22 connected to the heat source groups 10 and 20 is not changedsuddenly.

In the heat source system 100 according to the embodiment, the controlof the number of units and the load distribution in the plurality ofheat source groups 10 and 20 can be performed without considerablechange in the number of operating heat source units 12 and 22 connectedto the heat source groups 10 and 20. Further, the optimum operatingstate in which the power consumption is small can be kept as theoperating state of the heat source units 12 and 22.

Next, a second embodiment will be described with reference to FIG. 8.The same reference numerals are given to the same portions as those ofthe first embodiment. The description thereof will be omitted and onlydifferences will be described. FIG. 8 is a flowchart for describing abasic control operation of a heat source system 100 according to asecond embodiment.

When the load distribution to the heat source groups 10 and 20 from thenumber-of-units control device 30 is greater than an operatable loadrange of the number of operating heat source units, the heat sourcesystem 100 increases the number of operating heat source units in theheat source groups 10 and 20 and updates the optimum load range and theoperatable load range. Specifically, in the heat source system 100, forexample, when ten heat source units 12 are connected to the first groupcontrol device 11 (the load range that can be handled with the wholeheat source group is assumed to be 100%) and the load distribution fromthe number-of-units control device 30 is greater than 10% in the case ofan operating state of one unit (the operatable load range correspondingto the operating state is 10%), the number of operating units is updatedfrom one to two and the optimum load range for two heat source units andthe operatable load range for three heat source units are assumed to bethe optimum load range and the operatable load range of the whole heatsource group.

As illustrated in FIG. 8, when control starts, the first group controldevice 11 and the second group control device 21 determine whether theload distribution is greater than a Hi-side of an operatable load rangeof the operating heat source units (S201).

When the load distribution is greater than the Hi-side of the operatableload range of the operating heat source units, the first group controldevice 11 and the second group control device 21 increase the number ofoperating heat source units and update the optimum load range and theoperatable load range of both of the heat source groups 10 and 20.

At this time, when the load distribution is not greater than the Hi-sideof the operatable load range of the operating heat source units, thefirst group control device 11 and the second group control device 21 endthe process.

The heat source system 100 according to the embodiment can automaticallyincrease the number of operating heat source units of the heat sourcegroups 10 and 20 by increasing the load allocation once all thesubordinate heat source groups 10 and 20 are in an operating state ofone heat source unit from the viewpoint of the number-of-units controldevice 30.

Next, a third embodiment will be described with reference to FIG. 9. Thesame reference numerals are given to the same portions as those of thefirst embodiment. The description thereof will be omitted and onlydifferences will be described. FIG. 9 is a flowchart for describing abasic control operation of a heat source system 100 according to a thirdembodiment.

When the load distribution to the heat source groups from thenumber-of-units control device 30 is less than an operatable load rangeof the number of operating heat source units, the heat source system 100decreases the number of operating heat source units in the heat sourcegroups 10 and 20 and updates the optimum load range and the operatableload range. Specifically, for example, when ten heat source units areconnected to the group control devices 11 and 21 (the load range thatcan be handled with both of the heat source groups is assumed to be100%) and the load distribution from the number-of-units control device30 is less than 20% in the case of an operating state of two units (theoperatable load range corresponding to the operating state is 20%), thenumber of operating units is updated from two to one and the optimumload range for one heat source unit and the operatable load range fortwo heat source units are assumed to be the optimum load range and theoperatable load range of both of the heat source groups.

As illustrated in FIG. 9, when control starts, the first group controldevice 11 and the second group control device 21 determine whether theload distribution is less than a Lo-side of an operatable load range ofthe operating heat source units (S301).

When the load distribution is less than the Lo-side of the operatableload range of the operating heat source units, the first group controldevice 11 and the second group control device 21 decrease the number ofoperating heat source units and update the optimum load range and theoperatable load range of both of the heat source groups 10 and 20.

At this time, when the load distribution is not less than the Lo-side ofthe operatable load range of the operating heat source units, the firstgroup control device 11 and the second group control device 21 end theprocess.

The heat source system 100 according to the embodiment can automaticallydecrease the number of operating heat source units of the heat sourcegroups 10 and 20 by decreasing the load allocation once all thesubordinate heat source groups are in an operating state of theplurality of heat source units from the viewpoint of the number-of-unitscontrol device 30.

The heat source system and the heat source control method are notlimited to the above-described embodiments, but can be appropriatelymodified or improved.

INDUSTRIAL APPLICABILITY

It is possible to control the number of operating heat source unitsincluded in the plurality of heat source groups without sudden changes.

REFERENCE SIGNS LIST

-   -   100 Heat source system    -   10 First heat source group    -   11 First group control device    -   12, 22 Heat source unit    -   13, 23 Unit-integrated control device    -   14, 24 First operating-range output unit    -   15, 25 Second operating-range output unit    -   20 Second heat source group    -   21 Second group control device    -   30 Number-of-units control device    -   41 Water inlet    -   42 Water outlet

1. A heat source control device comprising: a plurality of group controlunits configured to perform start/stop and load allocation of aplurality of heat source units corresponding to heat source groups ofthe plurality of heat source units; and a number-of-units control unitconfigured to perform start/stop and load allocation of the heat sourcegroups, wherein the group control unit includes a first operating-rangeoutput unit configured to output a load range in which one ofcharacteristic values of the heat source units corresponding to thenumber of operating heat source units is within a predetermined range asa first proper operating range to the number-of-units control unit basedon the characteristic values of the heat source units, and a secondoperating-range output unit configured to output a load range in whichanother of the characteristic values is in the predetermined range as asecond proper operating range to the number-of-units control unit, andwherein the number-of-units control unit increases the number ofactivated heat source groups when a requested load exceeds the firstproper operating range.
 2. The heat source control device according toclaim 1, wherein the first operating-range output unit uses COPinformation indicating a relation between a coefficient of performanceand a load ratio as the characteristic value and outputs a load range inwhich one of the characteristic values corresponding to the number ofoperating heat source units is equal to or greater than a predeterminedvalue as the first proper operating range to the number-of-units controlunit, and wherein the second operating-range output unit outputs a loadrange in which another of the characteristic values is equal to orgreater than the predetermined value as the second proper operatingrange to the number-of-units control unit.
 3. The heat source controldevice according to claim 1, wherein the first operating-range outputunit uses inverter input information as the characteristic value andoutputs a load range in which one of the characteristic valuescorresponding to the number of operating heat source units is equal toor less than a predetermined value as the first proper operating rangeto the number-of-units control unit, and wherein the secondoperating-range output unit outputs a load range in which another of thecharacteristic values is equal to or less than the predetermined valueas the second proper operating range to the number-of-units controlunit.
 4. The heat source control device according to claim 1, whereinthe group control unit sets, as transmission data from the group controlunit, an optimum load range corresponding to the number of operatingheat source units among the connected heat source units and anoperatable load range corresponding to 1+the number of operating heatsource units.
 5. The heat source control device according to claim 4,wherein, when load distribution to the heat source groups from thenumber-of-units control unit is greater than the operatable load rangefor the number of operating heat source units, the number of operatingheat source units in the heat source group is increased and the optimumload range and the operatable load range are updated.
 6. The heat sourcecontrol device according to claim 5, wherein, when load distribution tothe heat source groups from the number-of-units control unit is lessthan the operatable load range for the number of operating heat sourceunits, the number of operating heat source units in the heat sourcegroup is decreased and the optimum load range and the operatable loadrange are updated.
 7. A heat source system comprising: the heat sourcecontrol device according to claim 6; and heat source groups of theplurality of heat source units.
 8. A heat source control methodcomprising: a plurality of group control steps of performing start/stopand load allocation of a plurality of heat source units corresponding toheat source groups of the plurality of heat source units; and anumber-of-units control step of performing start/stop and loadallocation of the heat source groups, wherein the group control stepincludes a first operating-range output step of outputting a load rangein which one of characteristic values of the heat source unitscorresponding to the number of operating heat source units is within apredetermined range as a first proper operating range in thenumber-of-units control step based on the characteristic values of theheat source units, and a second operating-range output step ofoutputting a load range in which another of the characteristic values isin the predetermined range as a second proper operating range in thenumber-of-units control step, and wherein, in the number-of-unitscontrol step, the number of activated heat source groups is increasedwhen a requested load exceeds the first proper operating range.